Java OutputStreamWriter flush()用法及代码示例

OutputStreamWriter类flush()方法

• flush() 方法可在java.io包。
• flush() 方法用于刷新此流。
• flush() 方法是一个非静态方法，它只能通过类对象访问，如果我们尝试使用类名访问方法，那么我们将得到一个错误。
• flush() 方法可能会在刷新流时抛出异常。
  IOException:在执行时遇到任何输入/输出错误时可能会抛出此异常。

用法:

    public void flush();

参数：

• 它不接受任何参数。

返回值：

该方法的返回类型是void，它什么都不返回。

例：

// Java program to demonstrate the example 
// of void flush() method 
// of OutputStreamWriter

import java.io.*;

public class FlushOfOSW {
 public static void main(String[] args) throws Exception {
  OutputStream os_stm = null;
  OutputStreamWriter osw_stm = null;
  InputStream is_stm = null;
  int val = 65;
  try {

   // Instantiates FileOutputStream and 
   // FileInputStream and OutputStreamWriter
   os_stm = new FileOutputStream("D:\\includehelp.txt");
   osw_stm = new OutputStreamWriter(os_stm);

   // Loop to write byte to the stream
   for (int i = 0; i < 3; ++i) {
    osw_stm.write(val);
    val++;
   }

   // By using flush() method is to
   // flush the stream
   osw_stm.flush();
   System.out.println("Stream Flushed...");

   is_stm = new FileInputStream("D:\\includehelp.txt");

   // Loop to read byte from the stream
   for (int i = 0; i < 3; ++i) {
    char ch = (char) is_stm.read();
    System.out.println("ch:" + ch);

   }

   osw_stm.close();
   System.out.println("Stream Closed Successfully....");

  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // with the help of this block is to
   // free all necessary resources linked
   // with the stream
   if (is_stm != null) {
    is_stm.close();
    if (os_stm != null) {
     os_stm.close();
    }
   }
  }
 }
}

输出

Stream Flushed...
ch:A
ch:B
ch:C
Stream Closed Successfully....